Lecture 8-Neurocytology 2 Flashcards
What does a dark staining nucleus on the Golgi stain signify?
Less activity-DNA is tightly wound
What are the leptomeninges?
the arachnoid and pia mater together
What separates the dura mater from touching the periosteum of the vertebral arches?
epidural fat (adipose tissue)
Where is the epidural space located in the spinal cord?
between the dural mater and periosteum of the vertebrae
Where is the epidural space found in the skull?
between the skull and its periosteum
Where is the subdural space found?
between the dura mater and the underlying arachnoid mater
Tearing of bridging vein is most likely to cause hemorrhaging into what space?
subdural space
Hemorrhaging of the middle meningeal artery is most likely to cause what type of hematoma?
epidural hematoma
What cells are responsible for immunological surveillance and patrol in the brain?
microglia
What type of glial cell are phagocytitic?
microglia
What type of glial cell is activated by injury and quickly migrates to the site of damage to mediate the inflammatory reaction?
microglia
Which type of glial cell produces myelin for the CNS?
oligodendrocyte
How many cells can one oligodendrocyte myelinate in the CNS? What about Schwann cells in the PNS?
CNS- 1 Oligodendrocyte can myelinate several cells
PNS- 1 Schwann cell can only myelinate one cell
What is the function of an astrocyte?
- provide structural support
- monitor ionic environment around neurons
- form scar in regions of CNS damage
- form the glial limitans
What glial cell contains the Glial Fibrillary Acidic (GFAP) intermediate filaments?
astrocytes
What is the glial limitans?
the astrocyte lining around blood vessels and pial surfaces in the brain
What type of glial cell lines blood vessels in the brain?
astrocytes
List the types of neuroglia.
Microglia- immune response
Macroglia
astrocytes-structural support, monitor env.
oligodendrocytes- myelinate
What are the 2 layers of the dura mater?
periosteal layer
meningeal layer
Which meningeal layer IS pain sensitive?
dura mater
What creates the dural sinuses?
separations in the periosteal and meningeal layers of the dura mater
What is the name for the dura between the two cerebral hemispheres?
falx cerebri
What is the name for the dura between the cerebrum and the cerebellum?
tentorium cerebelli
What passes through the tentorial notch in the tenorium cerebelli?
brain stem
What meningeal layer follows the contour of the brain?
pia mater
What is a cistern?
a large subarachnoid space
caused by discontinuities b/t the arachnoid/dura contour and the pia/brain contour
List 3 cisterns found in the brain.
interpeduncular
pontine
magna (inferior to cerebellum)
What is the function of the CNS?
cushions the brain in response to external forces
What is the function of the ependymal cells and where are they found?
ependymal cells line the cerebral ventricles and central canal of the spinal cord
move their cilia to contribute to the flow of CSF
What is the choroid plexus?
specialized vascular structure that secretes CSF
Where are the 4 choroid plexuses found?
1 in each of the lateral ventricles
1 in the third ventricle
1 in the forth ventricle
What is the function of the arachnoid granulations?
transport CSF into the dural sinuses
How is CSF drained into the venous system?
via the arachnoid granulations
Describe the flow of CSF.
lateral ventricles->3rd ventricle->cerebral aqueduct->4th ventricle->cerebellomedullary cistern->arachnoid granulations-> dural sinuses
Where does CSF go after it leave the 4th ventricle?
cerebellomedullary cistern
Where are the foraminae of Luschka Magendie found?
between the 4th ventricle and cerebellomedullary cistern
What can decreases in flow or blockages in CSF lead to?
hydrocephalus
What is meant by a circumventricular organ?
regions in the brain where there is no blood brain barrier (pineal body, pituitary gland, area postrema and the subfornical region)
List the 4 areas of the brain where the BBB does not exist.
pineal body
pituitary gland
area postrema
subfornical region
(aka circumventricular organs)
What are tanycytes?
specialized ependymal cells that surround and isolate the circumventricular regions where there is no BBB
List 4 areas in the brain where tanycytes would be found?
- Pineal body
- Pituitary gland
- Area postema
- Subfornical region
(these are the circumventricular regions that lack a BBB)
What forms the BBB?
- Endothelial cells joined by tight junctions
- Pericytes in the basement membrane to contribute to the structural integrity
- Astrocytic and feet that create the glial limitans surround the blood vessels
What types of substances can diffuse through the BBB?
lipophilic substances
What type of substances used facilitated transport to get through the BBB?
glucose
What types of substances use active transport to get through the BBB?
everything except lipophilic substances and glucose
What is the area postrema?
area of the medulla that monitors blood, detects toxins and initiates vomiting reflex
(circumventricular organ surrounded by tanycytes)
What is the function of the subfornical organ?
monitor osmolarity of blood (one of the 4 circumventricular organs in the brain surrounded by tanygytes)
List the 3 Brain barriers.
Arachnoid Barrier- tight jxn in arachnoid lining cells
Blood-CSF Barrier- tight jxn b/t choroid plexus cells
Blood-Brain Barrier-tight jxn b/t endothelial cells
Why is sleep beneficial to waste removal from neurons?
New research has shown that neurons shrink during sleep which allows more room for CSF to flow and remove waste from neurons
